linux-kernel - Re: IOMMU+DMAR causing NMIs-s (was: 4.7-rc6: NMI in intel

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Date:	Wed, 13 Jul 2016 12:18:59 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	Meelis Roos <mroos@...ux.ee>
Cc:	iommu@...ts.linux-foundation.org,
	Linux Kernel list <linux-kernel@...r.kernel.org>,
	David Woodhouse <dwmw2@...radead.org>
Subject: Re: IOMMU+DMAR causing NMIs-s (was: 4.7-rc6: NMI in intel_idle on HP
 Proliant G6)

On Wed, Jul 13, 2016 at 12:58:24PM +0300, Meelis Roos wrote:
> > > Just got http://kodu.ut.ee/~mroos/4.6-dmar-fault2.png when playing with 
> > > BIOS settings (disabling NUMA). It is the first time I see at least some 
> > > info in NMI decode.
> > 
> > This looks interesting. Can you please post output of 'lspci -vvv' and
> > 'lspci -t'?
> 
> Here.

Thanks. So device 00:1e.0 is a PCI-bridge which has some 32-bit
PCI-devices behind it. One of these devices tries to read address
0xb000, which is blocked by the IOMMU and causes the fault seen in the
screen-shot. The fault also causes a PCI-error which is then reported
through the NMI, causing your kernel panic.

So the 32bit PCI devices behind the bridge are:

01:03.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] ES1000 (rev 02) (prog-if 00 [VGA controller])
01:04.0 System peripheral: Compaq Computer Corporation Integrated Lights Out Controller (rev 03)
01:04.2 System peripheral: Compaq Computer Corporation Integrated Lights Out  Processor (rev 03)
01:04.4 USB controller: Hewlett-Packard Company Integrated Lights-Out Standard Virtual USB Controller (prog-if 00 [UHCI])
01:04.6 IPMI SMIC interface: Hewlett-Packard Company Integrated Lights-Out Standard KCS Interface (prog-if 01)

Can you try to disable this 'Lights Out' processor? Maybe it is causing
the issues. On the other side, the radeon driver for the ATI card is
also know for causing faults from time to time. Can you capture the
kernel messages right before a crash too?

Thanks,

	Joerg